1. Technical Field of the Invention
The present invention relates to: a drive controlling method for a carriage which can eliminate influences of cogging of a carriage drive motor for driving the carriage along a guide member and a periodic change of a carriage drive motor velocity caused by a motor pulley and the like for driving the carriage; a computer readable medium including a computer program for performing this controlling method; and an electronic apparatus provided with a carriage controlled by this controlling method.
2. Description of the Related Art
In some recording apparatuses in which a carriage performs reciprocating drive in a horizontal direction perpendicular to the direction of paper feed for printing paper so that printing is performed, ink drops are discharged from nozzles of a recording head mounted on the carriage, and thereby dropped on the surface of the printing paper so that printing is performed. The reciprocating drive in the horizontal direction of the carriage is performed by a carriage drive motor via a motor pulley. The carriage drive motor employed here is generally a DC motor. However, a brushless DC motor requires gaps referred to as slots between magnetic poles. Thus, the shaft of the DC motor does not revolve smoothly, and hence a vibration is generated, as is well-known. This vibration is called cogging in some cases, and generated periodically, as is well-known. Further, the motor pulley for the carriage has eccentricity depending on the machining accuracy of the motor pulley, and hence provides a part of the cause of a periodic velocity fluctuation in the carriage drive motor (See, Japanese Published Unexamined Patent Application No. 2002-356033).
The vibration of a relatively short period generated by cogging of the carriage drive motor and the like and the vibration of a relatively long period caused by eccentricity of the motor pulley and the like are unavoidable. These has caused vibrations in the carriage and hence nonuniformity in the recording pitch of the main scanning direction. Thus, in order to prevent the carriage vibration, countermeasures have been proposed such as providing a vibration absorbing mechanism in the carriage. However, this causes the problem of complexity in the apparatus.